Method for controlling the curing degree of at least one at least partially cured ink and/or varnish printed on a substrate

The present invention relates to a method for controlling the curing degree of at least one at least partially cured ink and/or varnish printed on a substrate, which comprises cutting at least one sample from an area of the printed substrate, placing and incubating it in a solvent, in which at least one of the at least one extractable compound is soluble, and removing it from the solvent to obtain a solvent extract; quantitatively measuring a spectroscopic characteristic of the solvent extract; comparing the measured numeric value of the spectroscopic characteristic with a reference value of the spectroscopic characteristic for the same area of the printed substrate; and outputting a result, wherein the reference value of the spectroscopic characteristic for the same area of the printed substrate has been obtained by the use of an empirical model.